Increasing demand for the delivery of multimedia content over mobile networks (e.g. mobile television) has intensified the appeal of delivering that content using broadcast technologies. Broadcast technologies entail the use of broadcast bearer services, such as Digital Video Broadcasting-Handheld (DVB-H) and Multimedia Broadcast Multicast Service (MBMS), that ensure more efficient network utilization. Unlike unicast bearer services (e.g. Packet-Switched Streaming over 3G), which consume a link for each subscriber even if the subscribers are demanding the same multimedia content in the same area, broadcast bearer services permit subscribers to share a single link for that same multimedia content. As the number of subscribers demanding that content decreases, however, so does the efficiency of broadcast delivery. Accordingly, network operators may decline to make broadcast delivery of certain multimedia content available everywhere and anytime.
In a hybrid unicast-broadcast delivery network, unicast delivery complements broadcast delivery where and when broadcast coverage for a certain multimedia stream is not available. That is, a mobile terminal detects when broadcast delivery of a certain multimedia stream becomes unavailable and changes to using unicast delivery for that stream. While such change permits delivery despite the lack of broadcast coverage, the mobile terminal should return to using the more efficient broadcast delivery if it becomes available again.
The time at which the mobile terminal changes back to using broadcast delivery, however, may affect both the efficiency of network utilization and the multimedia experience of the subscriber. If the mobile terminal changes back to using broadcast delivery before broadcast coverage is stable, for example, a ping-pong effect between unicast and broadcast delivery may result in significant data loss and interruption in the subscriber's multimedia experience. On the other hand, if the mobile terminal avoids this interruption by delaying the change for a potentially significant amount of time (e.g. until the subscriber changes the multimedia channel), network utilization becomes significantly more inefficient.